Food serves almost no official role in white, mainline, Protestant churches, according to historian Daniel Sack. Indeed, its very sensuousness is suspect. But the church-basement kitchen, lurking beneath the sanctuary, leads a kind of shadow ministry, he argues, calling the faithful with Jell-O at least as effectively as the sermon served upstairs. "Around the Communion table, bread and wine become a connection to God," Sack writes in "Whitebread Protestants: Food and Religion in American Culture." "In the social hall, coffee becomes community. In the soup kitchen, rice and beans become hospitality."

That food unites is hardly a novel thought. Sack explores some of the nuances of the connection between church and food with deep affection, if cursory insight. His book is most detailed, and most interesting, when it follows the changes in Communion from wine to grape juice (in response to the temperance movement) and from communal goblet to single-serve cups (in response to concerns about hygiene). Social practice, in turn, affects the religion:

"The individual cup, intended to prevent the spread of disease, has fostered an individualistic understanding of Communion. Afraid of contamination by others in church, whitebread Protestants have shifted their theology of the sacrament, focusing on the Communion of the individual and God rather than the Communion of the entire church." Or, as one critic has it: " 'Communion without communion!' "

Sack honors the beloved potluck, pausing for fond remembrance of fried chicken served on Formica tables in a light-green basement. He introduces its latest variation: the megachurch food mall. Sack, who lives in Naperville, chooses a local example, Willow Creek Community Church in Barrington. The food court, he reports, can serve up to 3,000 people in 15 minutes. It offers, he writes, "church supper for a free-market society."

Other trends explored thematically (not chronologically) include the churches' postwar, self-congratulatory efforts to feed Europe's poor and the 1970s self-flagellatory efforts to feed the Third World poor, largely through a meatless diet at home. There's a tour of various diet-reform movements and the products they yielded. Who knew we had our righteous capitalist brethren to thank for such kitchen staples as Welch's grape juice, graham crackers and Kellogg's Corn Flakes?

It's instructive to hear the advice of a homemaker who in 1886 won $250 from Good Housekeeping for an essay titled "How to Eat, Drink, and Sleep As a Christian Should." She recommends setting the table with flowers and linens. But it's significant -- and maddening -- that Sack makes no direct link between doctrine and custom. What he offers -- " 'eating as Christians should' meant eating like genteel middle-class Americans" -- is merely obvious.

In "The Bialy Eaters: The Story of a Bread and a Lost World," Mimi Sheraton records the death of a culture by focusing on its remaining food. She learns what she can about the bialy, the "runty onion roll" that once nourished a vibrant society of Jews in Bialystok, Poland.

Sheraton, a former food critic for The New York Times, has previously gone to great lengths in search of authenticity. In Copenhagen she tracked down real Danish pastry; in France, French toast; in Istanbul, Turkish delight. Her bialy journey, which occupied seven years (sandwiched between freelance magazine assignments), appears to be longer, more complicated and ultimately less successful than the others.

Sheraton approaches the bialy with sturdy prose and a warm heart. "It is not surprising that memories of a simple and runty onion roll should have evoked the bygone world of Bialystok Jews," she writes in the introduction. "To make a rather obvious comparison, the bialy worked in my research much as the madeleine did for Proust, although I feel that the pallid, effete recollections of a hermetic world summoned up by that spongy, sweet, shell-shaped cake do not hold a candle to the feisty and earthy experiences recalled by this yeasty, crusty roll. Most of the inhabitants of Proust's lost times were as fragile and delicate as the madeleine. The Bialystokers I encountered comprise a tough, resilient, streetwise bunch, cynical for the best of reasons yet full of broad humor, the very qualities one might expect of those whose palates are strong enough to tolerate a tough, charred roll topped with browned onions first thing in the morning."